The proposed project is a multidisciplined approach to the study of trophoblastic disease, employing in vivo and in vitro clinical and immunological methods. Broad objectives: a screening and early detection program of choriocarcinoma in patients whose antecedent pregnancy is premature and term pregnancy or abortion, a screening and early detection program of choriocarcinoma and invasive mole in patients whose antecedent pregnancy is hydatid mole, and evaluation of the effectiveness of the screening and detection program by the conduct of treatment and analysis of results. New clinical trials with adjuvant radiation therapy in metastatic choriocarcinoma and special therapy in non-metastatic choriocarcinoma to prevent or reduce incidence of metastatic disease will be conducted. Evaluation of the specific HCG-RIA test method in trophoblastic diseases will be made. Application of new approaches for evaluating patient tumor immunity will utilize immune recognition phenomenon as a focal point. The synthesis and release of HCG, a characteristic function of trophoblast, appears to be affected by immune attack. Other parameters of immunity including adherence, proliferation and cytotoxicity have not in our or other hands proved as useful. The role of erythocyte and leukocyte histocompatibility antigens and corresponding immune responses in trophoblastic cancer will be extended in the proposed studies by disease-factor association and the presence of specific humoral antibody. New and established lines of trophoblastic neoplastic tissue will be used to study the morphologic, physiologic and pharmacologic properties of trophoblastic disease.